Box with a breakable seal which is broken as the box is opened

A box comprising:

• at least three adjoining main panels defining a box body and separated from each other by first folding lines formed on a die cut flexible material sheet;
• at least one closure panel for said box, said closure panel projecting from one of said main panels and including a tongue which projects from said closure panel, said closure panel being separated from said tongue and from said one main panel by second folding lines, such that said tongue can be introduced into said box under at least a second one of said main panels;
• at least one elongated window provided through said tongue, said elongated window being defined by a substantially C-shaped cut made through said tongue, a central proton of said C-shaped cut being substantially parallel to one of said second folding lines which separates said tongue from said closure panel, said cut having two end portions which are slanted with respect to said central potion thereof and extend at least up to said one of said second folding lines for defining a lug projecting from said closure panel and coplanar therewith;
• at least one rotary flap projecting from at least a third one of said main panels, said rotary flap being adapted to turn about a third folding line which is between said flap and said third one of said main panels and being further adapted to be arranged under said closure panel;
• and
• at least one hook shaped tooth projecting from said flap, said hook shaped tooth having a side which faces said third folding line and is slanted such that said tooth has a free end portion with a largest width, said largest width of said tooth being smaller than a length of said window for permitting the tooth to extend through and project from said window when said closure panel is closed;
• wherein:
• at least a hole is formed though said lug of said closure panel, said hole being arranged above said tooth when said closure panel is closed;
• and
• a preset breakage line is formed on said flap for facilitating a separation of said tooth from said flap.